The motor responses of the proximal colon, sigmoid, and rectum to the ingestion of a standard meal have been compared in patients with total gastrectomy, pernicious anaemia, or duodenal ulcer. Colonic pressure activity increased during and after food in all the patients, but this was only once associated with propulsive activity. The results suggest that the postprandial pressure activity in the sigmoid colon is greater after total gastrectomy than in the other two groups. It is concluded that entry of food into the upper small intestine is the most important factor in initiating the colonic pressure response to food, since this response does not require the presence of the stomach, acid, antral gastrin, or of vagal innervation.